More merging assistence.

Logging behavior changed in early 5.1.  (The filename was never right, but
the "opt" file is unnecessary in 5.0 anyway.)


mysql-test/t/mysql_client_test-master.opt:
  Logging behavior changed in early 5.1.

mysql-test/t/mysql_client_test-master.opt

+--log --log-output=FILE 

mysql-test/t/mysql_client_test.opt

---log